Doom3world

I'm trying to create a setup with an articulated figure rope. I'd like one end of the rope anchored to a wall, and the other end attached to an idMoveable (i.e. barrel, crate). Here's an illustration of what I'm attempting:


(It can be seen as something like a ball & chain attached to a wall, or a sideways chandelier)


When I attach my rope to the idMoveable, it does attach successfully:The problem is, the entire rope gets attached: when I move the idMoveable around, the end of the rope rips out of the wall and follows the idMoveable around. It seems objects can only have one "bind" associated with them.

(The most straight-forward implementation would be to convert the entire thing into a single articulated figure mesh. But, I'd like for the player to be able to attach & reattach things to the rope, so converting the entire thing into a single mesh unfortunately isn't an option.)

Anyone have a scripting solution to this, or should I start digging around the SDK?

This should help: viewtopic.php?t=3529&highlight=bindconstraint

Thanks for the tip! I'm using bindConstraint to attach a specific joint to my idMoveable. But, my problem is I can't figure out how to have an articulated figure be anchored to two separate things (the wall and the idMoveable).

Also, the accompanying "bind" call seems to be all-or-nothing - it slaves the entire entity to the master, not just a part of it. Unless I'm misunderstanding how bindConstraint works?

Take a look at the hanging lights. They're AF's & can have a bulb bound to them but they stay where you put them.

You could also modify the previous idmovable and add the chain to it & the bones. Then just use that entity instead of two.

@The Happy Friar - it seems for Doom3's hanging lights, the bulb is the child & the light fixture chain is the parent.

In my particular case, I need that relationship flipped - the attached object (the bulb) to be the parent, and the chain to be the child (so that when the object moves, the chain follows suit). But the problem is when I slave the chain to the object, the chain no longer has any attachment to worldspawn.

Unfortunately, I can't merge the two objects into one mesh - for gameplay reasons, I'd like for the player to be able to attach and reattach idMoveables to the end of the chain.

But for the hanging lights (they don't include bulbs or a light) you bind the bulb object AND the light TO the hanging light. Not the hanging light TO the bulb/light, like you said. That's what you should to:

myMoveable.bind(myRope);

From the looks of it you're looking the info on "myMovable" (barrel) and wanting to attach it to the rope. Since you know the rope's name (it's placed via the editor, after all) you can do the same type of lookup just change what you bind to.

Unless there's something I'm missing.

@The Happy Friar - I made a short video of my test case-
http://youtu.be/m5H8LajiT6A

The four crates are set up in different ways:

BOX 1: Normal box, nothing bound to/from it.

BOX 2: bound via: myMoveable.bind(myRope);
When player pushes against the box, the box does not react in any way.

BOX 3: bound via: myMoveable.bindToJoint( myRope, "bone5", false );
No reaction from box, identical to box 2.

BOX 4: bound via:
myRope.setKey( "bindConstraint name1", "ballAndSocket bone4 bone4" );
myRope.bind(myMoveable);
The box does react when I push against it. However, it pushes the entire rope fixture away from its original spot.

My goal is to make a "chandelier"-type setup where I can push/interact with the box, but keep the rope fixture attached to both the ceiling & the box. Child objects seem to have limited physics, which is why I was attempting to flip the child/parent relationship.

I get a message saying the video is private.

Whoops! Video should be viewable now.

Ok, I see what it is doing: just like how the box wouldn't move when you pushed it when it was bound to the light but it did move when you moved the light, in the last case the box is moving the light but I bet if you moved the light it wouldn't move.

Ok, I got this to work... in the editor:

I took an env_hellchain & a movable_cartonbox1. In the editor I placed the box at the bottom of the chain. for the box I did this:
bind env_hellchain_1
bindtojoint joint8

This bound it to the chain and specifically to the joint8 bone. It worked as expected.

Doesn't help for "on the fly" binding though, this is what I did in the script:
$moveable_cartonbox1_1.bindToJoint($env_hellchain_1, "joint8", 1);

That worked perfectly.

I'm betting your issue is the lack of "$" in front of your entity names.

@The Happy Friar
That won't solve the problem. If you shoot to the box, the chain won't move. I guess this is what blender81 is talking about, you cannot move the parent by moving its child.
Also, I've took a look to the SDK and it seems that you cannot bind an entity to two other entities simultaneously, this would mean that if you bind a child entity to its master, you lose any previous bind of the child. This is the reason why the chain ( or rope or whatever else ) detaches from its original anchor point in the 4th binding of the video.

I guess you cannot do anything without some work on the SDK, but I'd like to take a look if we can do something with some tricks.

Regards

I copied your setup, and I still seem to be having the same issue - in your test map, does the box react when you walk against it? If so, can you upload your .map and .script file? When my box is slaved to the chain, my box has no reaction when I bump up against it.

Here's a video of what I'm seeing:
http://youtu.be/TXogWChteok

I get the impression that child objects are treated like second-class citizens. In the video, my slaved box constantly sinks into geometry, but its parent chain never penetrates any world brushes.

The parented box/slaved chain likewise seem to show the same behavior - the parented box never penetrates world geometry, but the slave chain constantly does.

(I also double-checked my script - it does have the $ marks; I neglected to include them in my previous post)

@doomtrinity - punching/shooting the box actually does make the chain react, though only in certain cases (such as a hanging chandelier setup). It starts to act very squirrelly in other situations, such as a ball-and-chain attached to a wall.

I've also been poking through the SDK. The BindConstraint tags are able to constrain an object at multiple joints, but as you said, the problem is that they'll all be slaved to one singular master.

If the box isn't moving when shot it's because it's not activated for physics yet. It may need to be touched.

I'll upload my map/script after work. Before you didn't mention you didn't want to child to not penetrate geometry.

I'm also pretty sure you can have a chain of bind setup, I've done it before but I don't remember what the point was or how it reacted.

Here's my test map. Things to remember:
*AF's only work on objects with bones, the boxes don't have bones.
*The physics is expected to work in a "real" situation, not a "fake" one with the use of "G_dragentity" to pull/push things unrealistically.
*Physics is disabled until the objected is activated via touching.

@The Happy Friar - thanks for the test map!

The boxes do react to punching, but do not react to other physics impulses (walking into them, shooting them). Does your build show something different?

Here's a video of what I'm seeing:
http://youtu.be/UZ98ggkUXUA

Yes, mine react when I walk in to them. I'm using the latest D3 patch, I don't have the Steam one. Even if they don't react at first, after you hit them they should react to walking in to them.

That's so strange - perhaps it's a difference with the builds? My console reads 1.3.1.1304

I've tried it with default Doom3 & RoE on Steam, and my own compiled executable, and they all display the same behavior. I'll have to dig in and see what's causing this difference.

Maybe I have a custom def for something in my edit folder.

If I did then it might work for me because it uses the entity's mass to determine how it moves. Since punching has more force it moves more mass. Rockets to do. The pistol doesn't. Etc.

Do you have a limited number of entities you would like atttached to the rope? maybe could make it into one entity with all models incorporated at the end and hide/show them with skins?

Could maybe also fake it through scripting, attach the moveable to the end (or model of, hiding original moveable), place a clip model same bounds at end to stop the child falling through the geometry (as childs seem to do) and fake the moveable part while its attached using a forcefield again same bounds as model plus a couple of units.

Just a couple of quick ideas for a fix.

S@TaNiC - those are great suggestions! For now I've decided to scale back my design and freeze all the objects once the rope+moveable are connected. It's not ideal, but I don't want to get roadblocked on this one feature for too long.

When I do find more time, I'd like to give your clip model idea a try, I think it could possibly work.